JP2011159432A - Light-emitting element, lighting system, and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting element which can superbly extract light in a wide wavelength band, and aim at greatly reducing viewing angle dependency of luminance and hues of a single or a plurality of colors on light of synthetic colors. <P>SOLUTION: The light-emitting element includes a first light-emitting layer 13a and a second light-emitting layer 13b emitting light of a single color or two or more kinds of different colors of a visible light region in an organic layer 13 pinched between a first electrode 11 and a second electrode 12. A first reflecting interface 15 is formed at a first electrode 11 side. A second reflecting interface 16 and a third reflecting interface 17 are formed at a second electrode 12 side. Reflection of light by at least either the second reflecting interface 16 or the third reflecting interface 17 is so set in conditions of strengthening or weakening against a central wavelength of an emission spectrum of the first light-emitting layer 13a and a central wavelength of an emission spectrum of the second light-emitting layer 13b in shifting interference wavelengths. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light-emitting element, an illumination device, and a display device, and more particularly, to a light-emitting element that uses electroluminescence of an organic material, and an illumination device and a display device that use the light-emitting element.

  Light-emitting elements that use electroluminescence of organic materials (hereinafter referred to as “organic EL elements”) are attracting attention as light-emitting elements that can emit light with high luminance by low-voltage direct current drive, and are actively researched and developed. This organic EL element generally has a structure in which an organic layer including a light emitting layer having a thickness of about several tens to several hundreds of nanometers is sandwiched between a reflective electrode and a translucent electrode. In such an organic EL element, light emitted from the light emitting layer interferes in the element structure and is extracted outside. Conventionally, attempts have been made to improve the light emission efficiency of organic EL elements by utilizing such interference.

  In Patent Document 1, the distance from the light emitting position to the reflective layer is determined by using the interference between the light emitted from the light emitting layer in the direction of the translucent electrode and the light emitted in the direction of the reflective electrode. It has been proposed to increase the light emission efficiency by setting so that the light of the laser beam resonates.

  In Patent Document 2, in consideration of light reflection at the interface between the translucent electrode and the substrate, the distance from the light emitting position to the reflective electrode, and the distance from the light emitting position to the interface between the translucent electrode and the substrate. And stipulates both.

  In Patent Document 3, the thickness of the layer between the translucent electrode and the reflective electrode is desired by utilizing interference caused by multiple reflection of light between the translucent electrode and the reflective electrode. Luminous efficiency is increased by setting so that light of a wavelength resonates.

  In Patent Document 4, the thickness of the organic layer is controlled as a method for improving the viewing angle characteristics of the white chromaticity point in a display device in which a light emitting element having a light emitting efficiency increased using a resonator structure is combined. Has proposed a method of controlling the balance of attenuation of the three colors red (R), green (G) and blue (B).

  However, in the above-described conventional technology, in the organic EL element that uses the interference of the emitted light in order to increase the light emission efficiency, when the bandwidth of the interference filter for the extracted light h is narrowed, the light emitting surface is inclined from an oblique direction. When viewed, the viewing angle dependency of the light emission characteristics is increased, for example, the wavelength of the light h is greatly shifted and the light emission intensity is reduced.

  On the other hand, in Patent Document 5, the phase of light emission by the reflective layer of the organic EL element having a narrow band monochromatic spectrum and the interference by the reflective layer provided on the exit side are opposite in phase to the center wavelength. It has been proposed to suppress the hue change due to the viewing angle.

  In addition, even in an organic light emitting device having a white light emitting layer that is sequentially stacked, the above-described interference exists inside the device. Therefore, in order to efficiently extract white light having a wide range of wavelength components, the light emitting position is used as a reflective layer. It is preferable to make them approach, particularly close to a distance of 80 nm or less. When the light emission position is away from the reflection layer and the distance is increased, it becomes difficult to obtain white light emission having a wide spectrum due to interference.

  In Patent Document 6, by defining the distance from the light emitting position to the reflective layer and the distance from the light emitting position to the interface between the translucent electrode and the outer layer, the light emitting element having excellent white chromaticity is obtained. Is disclosed.

  In Patent Document 7, it is reported that a good white chromaticity point can be obtained by incorporating anti-phase interference similar to that in Patent Document 5. However, since phase cancellation cannot be performed in a wide wavelength band, there is no mention of hue change suppression by a viewing angle such as a single color as in Patent Document 5.

  On the other hand, in order to increase the light emission efficiency and improve the light emission lifetime, a plurality of light emitting layers are stacked via an intermediate layer so that the light emitting layers have a stacked structure (so-called tandem structure) connected in series. A technique for forming an organic layer is known (see, for example, Patent Documents 8 to 10). In this type of organic layer, any number of light emitting layers can be stacked. In this case, in particular, by laminating a blue light emitting layer for generating blue light, a green light emitting layer for generating green light, and a red light emitting layer for generating red light, the blue light, green light and It is possible to generate white light as the combined light of red light.

  However, when the tandem structure as described above is formed, it is difficult to configure all the distances from the respective light emitting positions to the reflection layer to be 80 nm or less, and the viewing angle dependency of luminance and hue becomes very high. As a light distribution characteristic or a display characteristic as a display device.

JP 2002-289358 A JP 2000-243573 A International Publication WO01 / 039554 Pamphlet Japanese Patent No. 3508741 JP 2006-244713 A JP 2004-79421 A JP 2006-244712 A JP 2006-173550 A Special table 2008-511100 gazette Special table 2008-518400

Accordingly, the problem to be solved by the present invention is that light can be extracted well in a wide wavelength band, and the luminance and hue viewing angle dependence for light of a single color or a composite color of a single color is greatly reduced. It is to provide a light-emitting element that can be realized.
Another problem to be solved by the present invention is to provide an illuminating device with less angle dependency and good light distribution characteristics.
Still another problem to be solved by the present invention is to provide a high-quality display device with less viewing angle dependency.

In order to solve the above problems, the present invention provides:
A first light emitting layer and a second light emitting layer, which are sandwiched between a first electrode and a second electrode and emit light of a single color in a visible light region or different colors of two or more colors, are provided in the first light emitting layer. An organic layer sequentially including at positions separated from each other in a direction from the electrode toward the second electrode;
A first reflective interface provided on the first electrode side for reflecting light emitted from the first light-emitting layer and the second light-emitting layer and emitting the light from the second electrode side; ,
A second reflective interface and a third reflective interface sequentially provided at positions separated from each other in a direction from the first electrode toward the second electrode on the second electrode side;
The optical distance between the first reflective interface and the light emission center of the first light emitting layer is L11, and the optical distance between the first reflective interface and the light emission center of the second light emitting layer is L21, L12 represents the optical distance between the light emitting center of the first light emitting layer and the second reflective interface, and L22 represents the optical distance between the light emitting center of the second light emitting layer and the second reflective interface. L13 represents an optical distance between the light emitting center of the first light emitting layer and the third reflective interface, and L23 represents an optical distance between the light emitting center of the second light emitting layer and the third reflective interface. When the central wavelength of the emission spectrum of the first light emitting layer is λ1 and the central wavelength of the emission spectrum of the second light emitting layer is λ2, L11, L21, L12, L22, L13 and L23 are expressed by the following formula (1 ) To (6) are satisfied, and a smaller number of the formulas (7) and (8) The light-emitting element satisfies at least one of them.
2L11 / λ11 + φ1 / 2π = 0 (1)
2L21 / λ21 + φ1 / 2π = n (where n ≧ 1) (2)
λ1-150 <λ11 <λ1 + 80 (3)
λ2-30 <λ21 <λ2 + 80 (4)
2L12 / λ12 + φ2 / 2π = m ′ + 1/2 and 2L13 / λ13 + φ3 / 2π = m ″ or 2L12 / λ12 + φ2 / 2π = m ′ and 2L13 / λ13 + φ3 / 2π = m ″ +1/2 (5)
2L22 / λ22 + φ2 / 2π = n ′ + 1/2 and 2L23 / λ23 + φ3 / 2π = n ″ or 2L22 / λ22 + φ2 / 2π = n ′ and 2L23 / λ23 + φ3 / 2π = n ″ +1/2 or 2L22 / λ22 + φ2 / 2π = n ′ + 1/2 and 2L23 / λ23 + φ3 / 2π = n ″ +1/2 (6)
λ22 <λ2-15 or λ23> λ2 + 15 (7)
λ23 <λ2-15 or λ22> λ2 + 15 (8)
However, m ′, m ″, n, n ′, n ″: integers λ1, λ2, λ11, λ21, λ12, λ22, λ13, λ23 are in units of nm.
φ1: Phase change when light of each wavelength is reflected by the first reflection interface φ2: Phase change when light of each wavelength is reflected by the second reflection interface φ3: Light of each wavelength is the third Phase change when reflected at the reflective interface

In addition, this invention
Having at least one light emitting element,
The light emitting element is
A first light emitting layer and a second light emitting layer, which are sandwiched between a first electrode and a second electrode and emit light of a single color in a visible light region or different colors of two or more colors, are provided in the first light emitting layer. An organic layer sequentially including at positions separated from each other in a direction from the electrode toward the second electrode;
A first reflective interface provided on the first electrode side for reflecting light emitted from the first light-emitting layer and the second light-emitting layer and emitting the light from the second electrode side; ,
A second reflective interface and a third reflective interface sequentially provided at positions separated from each other in a direction from the first electrode toward the second electrode on the second electrode side;
The optical distance between the first reflective interface and the light emission center of the first light emitting layer is L11, and the optical distance between the first reflective interface and the light emission center of the second light emitting layer is L21, L12 represents the optical distance between the light emitting center of the first light emitting layer and the second reflective interface, and L22 represents the optical distance between the light emitting center of the second light emitting layer and the second reflective interface. L13 represents an optical distance between the light emitting center of the first light emitting layer and the third reflective interface, and L23 represents an optical distance between the light emitting center of the second light emitting layer and the third reflective interface. When the central wavelength of the emission spectrum of the first light emitting layer is λ1 and the central wavelength of the emission spectrum of the second light emitting layer is λ2, L11, L21, L12, L22, L13 and L23 are expressed by the above formula (1 ) To (6) are satisfied, and a smaller number of the formulas (7) and (8) The lighting device satisfies at least one of the requirements.

In addition, this invention
Having at least one light emitting element,
The light emitting element is
A first light emitting layer and a second light emitting layer, which are sandwiched between a first electrode and a second electrode and emit light of a single color in a visible light region or different colors of two or more colors, are provided in the first light emitting layer. An organic layer sequentially including at positions separated from each other in a direction from the electrode toward the second electrode;
A first reflective interface provided on the first electrode side for reflecting light emitted from the first light-emitting layer and the second light-emitting layer and emitting the light from the second electrode side; ,
A second reflective interface and a third reflective interface sequentially provided at positions separated from each other in a direction from the first electrode toward the second electrode on the second electrode side;
The optical distance between the first reflective interface and the light emission center of the first light emitting layer is L11, and the optical distance between the first reflective interface and the light emission center of the second light emitting layer is L21, L12 represents the optical distance between the light emitting center of the first light emitting layer and the second reflective interface, and L22 represents the optical distance between the light emitting center of the second light emitting layer and the second reflective interface. L13 represents an optical distance between the light emitting center of the first light emitting layer and the third reflective interface, and L23 represents an optical distance between the light emitting center of the second light emitting layer and the third reflective interface. When the central wavelength of the emission spectrum of the first light emitting layer is λ1 and the central wavelength of the emission spectrum of the second light emitting layer is λ2, L11, L21, L12, L22, L13 and L23 are expressed by the above formula (1 ) To (6) are satisfied, and a smaller number of the formulas (7) and (8) The display device satisfies at least one of the requirements.

  The light emission centers of the first light emitting layer and the second light emitting layer mean a surface on which the peak of the light emission intensity distribution in the thickness direction is located. In a light emitting layer that emits monochromatic light, the emission center is usually a surface that bisects the thickness. When a light emitting layer that emits light of two or more different colors emits light of each color and the light emission center can be regarded as the same because the thickness of the layer that emits light of each color is sufficiently small, this light emission center usually has a thickness of It is a surface that bisects.

  Equation (1) indicates the optical distance between the first reflective interface and the emission center of the first light emitting layer, and the light having the center wavelength of the emission spectrum of the first light emitting layer is the first reflective interface and the first emission interface. This equation is set so as to be strengthened by interference with the light emission center of the light emitting layer. Equation (2) indicates the optical distance between the first reflective interface and the emission center of the second light emitting layer, and the light having the center wavelength of the emission spectrum of the second light emitting layer is the second reflection layer and the second reflection layer. This equation is set so as to be strengthened by interference with the light emission center of the light emitting layer. Equations (5) and (6) indicate that at least one of the reflection of light by the second reflection interface and the reflection of light by the third reflection interface is the center wavelength of the emission spectrum of the first light emitting layer and the second emission. This is an equation for setting a strengthening condition and a weakening condition while shifting the interference wavelength with respect to the center wavelength of the emission spectrum of the layer (λ12 ≠ λ13 or λ22 ≠ λ23). Expressions (7) and (8) are conditions for widening the interference wavelength. Λ11, λ21, λ12, λ22, λ13, and λ23 in equations (1), (2), (5), and (6) are obtained from λ1 and λ2 according to equations (3), (4), (7), and (8). Desired.

  m ′, m ″, n, n ′, and n ″ are selected as necessary. In order to increase the amount of light that can be extracted from the light emitting element, it is preferable to satisfy n ≦ 5, and most preferably n = 1 or n = 2.

  According to this light emitting element, the peak of the spectral transmittance curve of the interference filter can be made substantially flat in the visible light region, or the slopes of all the emission color bands can be made almost equal to each other. For this reason, the decrease in luminance when the viewing angle is 45 degrees can be 30% or less and the chromaticity deviation Δuv ≦ 0.015 with respect to the luminance when the viewing angle is 0 degrees.

  This light emitting element may be configured as a top emission type or a bottom emission type. In a top emission type light-emitting element, a first electrode, an organic layer, and a second electrode are sequentially stacked over a substrate. In a bottom emission type light emitting element, a second electrode, an organic layer, and a first electrode are sequentially stacked on a substrate. The substrate of the top emission type light emitting element may be opaque or transparent, and is selected as necessary. The substrate of the bottom emission type light emitting element is transparent in order to extract light emitted from the second electrode side to the outside.

  If necessary, a metal layer having a thickness capable of transmitting visible light, for example, a thickness of 5 nm or less, preferably 3 to 4 nm or less may be provided between the second light emitting layer and the second electrode. . This metal layer can be used as a translucent reflective layer.

  If necessary, one or more reflective interfaces may be provided in addition to the first reflective interface, the second reflective interface, and the third reflective interface. Further, if necessary, at least one of the first reflective interface, the second reflective interface, and the third reflective interface may be divided into a plurality of reflective interfaces. By doing so, the wavelength band in which the reflection of light by the second reflection interface and the reflection of light by the third reflection interface are weakened is expanded, and the flat portion of the peak of the spectral transmittance curve of the interference filter for each light emitting region is increased. The viewing angle characteristics can be improved by widening.

  When the light emission center of the light emitting layer that emits light of two or more different colors among the first light emitting layer and the second light emitting layer cannot be regarded as the same, the light emitting element is an interference filter of the light emitting element. It is preferable to further have a reflective layer for maintaining the flatness of the peak of the spectral transmittance curve. The reason why the emission centers of light emitting layers emitting two or more different colors of light cannot be regarded as the same is the increase in the thickness of the layers emitting light of each color, the stacking order of these layers, and the like.

  In this light emitting element, a reflective layer may be further formed due to the improvement of reliability, the configuration to be adopted, and the like, and thereby a reflective interface may be further formed. In that case, after forming up to the third reflective interface necessary for optical operation, it is possible to almost ignore the influence of the subsequent interference by forming a layer having a thickness of at least 1 μm on it. Become. In this case, any material outside the third reflective interface can be used, and is appropriately selected according to the form of the light emitting element. Specifically, the outside of the third reflective interface is formed by any one or two or more of a transparent electrode layer having a thickness of 1 μm or more, a transparent insulating layer, a resin layer, a glass layer, an air layer, It is not limited to this.

  The illumination device and display device of the present invention can have a conventionally known configuration, and are appropriately configured according to their use and function. In a typical example, a display device is provided with a drive substrate provided with an active element (such as a thin film transistor) for supplying a display signal corresponding to each display pixel to a light emitting element, and facing the drive substrate. And a sealed substrate. The light emitting element is disposed between the driving substrate and the sealing substrate. This display device may be any one of a white display device, a monochrome display device, a color display device, and the like. In a color display device, typically, a color filter that transmits light emitted from the second electrode side is provided on a substrate on the second electrode side of the light emitting element among the driving substrate and the sealing substrate.

  According to the present invention, light can be extracted well in a wide wavelength band, and the luminance and hue viewing angle dependence for a composite color of two or more different colors in a single color or visible light region can be greatly reduced. A light-emitting element that can be realized can be realized.

  In addition, according to the present invention, by using the light emitting element described above, it is possible to realize an illuminating device having a small angle dependency, a good light distribution characteristic, and a high image quality display device having a small viewing angle dependency. it can.

It is sectional drawing which shows the organic EL element by 1st Embodiment of this invention. It is a basic diagram which shows the spectral transmittance curve of the interference filter by the 1st reflective interface in the organic EL element by 1st Embodiment of this invention. It is a basic diagram which shows the spectral transmittance curve of the interference filter by the 1st reflective interface and the synthetic | combination interference filter of the 1st reflective interface and the 2nd reflective interface in the organic EL element by 1st Embodiment of this invention. . It is a basic diagram which shows the spectral transmittance curve of the synthetic | combination interference filter of the 1st reflective interface in the organic EL element by 1st Embodiment of this invention, a 2nd reflective interface, and a 3rd reflective interface. It is a basic diagram which shows the viewing angle characteristic of the brightness | luminance of the organic EL element by 1st Embodiment of this invention. It is a basic diagram which shows the viewing angle characteristic of the chromaticity of the organic EL element by 1st Embodiment of this invention. It is sectional drawing which shows the case where the light emission center cannot be considered the same because the thickness of the 2nd light emitting layer in the organic EL element by 1st Embodiment of this invention is large. It is a basic diagram which shows the spectral transmittance curve of the interference filter corresponding to the 2nd light emitting layer in the organic EL element shown in FIG. It is sectional drawing which shows the organic EL element by the 3rd Embodiment of this invention. It is a basic diagram which shows the spectral transmittance curve of the interference filter corresponding to the 2nd light emitting layer in the organic EL element by the 3rd Embodiment of this invention. It is a basic diagram which shows the viewing angle characteristic of the brightness | luminance of the organic EL element by 3rd Embodiment of this invention. It is a basic diagram which shows the viewing angle characteristic of the chromaticity of the organic EL element by 3rd Embodiment of this invention. 1 is a cross-sectional view showing a top emission organic EL element according to Example 1. FIG. 5 is a cross-sectional view showing a bottom emission type organic EL device according to Example 2. FIG. It is sectional drawing which shows the organic electroluminescent illuminating device by 4th Embodiment of this invention. It is sectional drawing which shows the organic electroluminescence display by the 5th Embodiment of this invention.

Hereinafter, modes for carrying out the invention (hereinafter referred to as “embodiments”) will be described. The description will be given in the following order.
1. First embodiment (organic EL element)
2. Second embodiment (organic EL element)
3. Third embodiment (organic EL element)
4). Fourth embodiment (organic EL lighting device)
5. Fifth embodiment (organic EL display device)

<1. First Embodiment>
[Organic EL device]
FIG. 1 shows an organic EL device according to the first embodiment.
As shown in FIG. 1, in this organic EL element, the first electrode 11 and the second electrode 12 are spaced apart from each other in the direction from the first electrode 11 to the second electrode 12. An organic layer 13 including a first light emitting layer 13a and a second light emitting layer 13b in this order is sandwiched. For the organic layers 13 above and below the first light emitting layer 13a and above and below the second light emitting layer 13b, a hole injection layer and a hole transport layer are formed as necessary, as in the case of a conventionally known organic EL device. , An electron transport layer, an electron injection layer, and the like are provided. In this case, the second electrode 12 is a transparent electrode that transmits visible light, and light is emitted from the second electrode 12 side. The 1st light emitting layer 13a and the 2nd light emitting layer 13b light-emit the light of a mutually different color of 2 colors or more of a single color or visible region. The light emission wavelengths of the first light emitting layer 13a and the second light emitting layer 13b are appropriately selected according to the color of light to be emitted from the organic EL element. Here, it is assumed that the first light emitting layer 13a emits two different colors of light in the visible light region, and the second light emitting layer 13b emits monochromatic light. In this case, the first light emitting layer 13a is composed of two light emitting layers a1 and a2 that emit light of different colors. For example, when this organic EL element is used as a white light emitting element, green and red light is emitted from the first light emitting layer 13a. In this case, green light is emitted from the light emitting layer a1, and red light is emitted from the light emitting layer a2. Further, blue light is emitted from the second light emitting layer 13b. The thicknesses of the light emitting layers a1 and a2 are selected to be sufficiently small so that the light emission centers of the light emitting layers a1 and a2 can be regarded as the same. A conductive transparent layer 14 is provided between the organic layer 13 and the second electrode 12. The transparent layer 14 may be composed of two or more layers as necessary. The first electrode 11, the second electrode 12, the organic layer 13, the first light emitting layer 13 a, the second light emitting layer 13 b, and the transparent layer 14 can be composed of conventionally known materials, and can be selected as necessary. Is done.

  The refractive index of the organic layer 13 is different from the refractive index of the first electrode 11, and a first reflective interface 15 is formed between the first electrode 11 and the organic layer 13 due to the difference in refractive index. The first reflective interface 15 may be provided at a position away from the first electrode 11 as necessary. The first reflective interface 15 has a role of reflecting light emitted from the first light emitting layer 13a and the second light emitting layer 13b and emitting the light from the second electrode 12 side. The refractive index of the transparent layer 14 is different from the refractive index of the organic layer 13, and a second reflective interface 16 is formed between the organic layer 13 and the transparent layer 14 due to the difference between these refractive indexes. Further, the refractive index of the transparent layer 14 is different from the refractive index of the second electrode 12, and a third reflective interface 17 is formed between the transparent layer 14 and the second electrode 12 due to the difference in refractive index. Yes.

  In FIG. 1, L11, L21, L12, L22, L13, and L23 are entered at the corresponding locations. In this organic EL element, L11, L21, L12, L22, L13 and so on are satisfied so that all of the formulas (1) to (6) are satisfied and at least one of the formulas (7) and (8) is satisfied. L23 is set.

The case where the organic EL element is a white light emitting element will be described in detail.
In this white light emitting organic EL element, the first light emitting layer 13a emits green and red light, the second light emitting layer 13b emits blue light, and white light is synthesized as a composite color of these colors. Take out. The center wavelength λ2 of the emission spectrum of the first light emitting layer 13a is, for example, 575 nm, and the center wavelength λ1 of the emission spectrum of the second light emitting layer 13b is, for example, 460 nm.

  L11 is set so that the light having the center wavelength λ1 of the emission spectrum of the first light emitting layer 13a is intensified by interference between the first reflective interface 15 and the light emission center of the first light emitting layer 13a. L21 is set so that the light having the center wavelength λ2 of the emission spectrum of the second light emitting layer 13b is strengthened by interference between the first reflective interface 15 and the light emission center of the second light emitting layer 13b. . This state is represented by the following formula, which satisfies the formulas (1) to (4). At this time, since the first light-emitting layer 13a is in a position where interference of the 0th order (see Equation (1)) occurs, the transmittance is high over a wide band (the first light-emitting layer 13a shown in FIG. The interference wavelength can be greatly shifted from the center wavelength λ1 of the emission spectrum as shown in equation (3).

2L11 / λ11 + φ1 / 2π = 0 (1) ′
2L21 / λ21 + φ1 / 2π = 1 (2) ′
However,
λ1-150 = 425 <λ11 = 540 <λ1 + 80 = 655 nm (3) ′
λ2-30 = 430 <λ21 = 480 <λ2 + 80 = 460 + 80 = 540 nm
(4) '

Here, φ1 is n and k of the complex refractive index N = n−jk (n: refractive index, k: extinction coefficient) of the first electrode 11 and the organic layer in contact with the first electrode 11. It can be calculated using a refractive index n _{0 of} 13 (see, for example, Principles of Optics, Max Born and Emil Wolf, 1974 (PERGAMON PRESS)). The refractive indexes of the organic layer 13 and the transparent layer 14 can be measured using a spectroscopic ellipsometry measuring device.

A specific example of the calculation of φ1 is shown below. If the first electrode 11 is made of an aluminum (Al) alloy, n = 0.908, k = 5... For light having a wavelength of 575 nm (corresponding to the center wavelength λ1 of the emission spectrum of the first light emitting layer 13a). 927. When the refractive index n ₀ of the organic layer 13 is 1.75, φ1 = tan ⁻¹ {(2n ₀ k / (n ² + k ² −n ₀ ² ))}
= Tan ^-1 (0.577)
It becomes. Considering that −2π <φ1 ≦ 0, it can be obtained as φ1 = −2.618 radians. Substituting this value of φ1 into equation (1) ′ to obtain L11 yields L11 = 114 nm. Further, when L21 is obtained by substituting the value of φ1 into the equation (2) ′, L21 = 340 nm.
When the refractive index n of the first electrode 11 is larger than the refractive index n ₀ of the organic layer 13, φ1 is further shifted by π radians, and when it is smaller, the shift amount is zero.

  At this time, the state of the interference filter with respect to the first light-emitting layer 13a and the second light-emitting layer 13b is in an intensifying condition, so that the spectral transmittance curve has a peak portion as shown in FIG. 2, and light extraction is improved. However, observation from an oblique direction shifts the wavelength band of the interference filter in the short wavelength direction, resulting in luminance and hue changes. Furthermore, since the band of the interference filter corresponding to the second light emitting layer 13b is shifted in the long wavelength direction, white light cannot be extracted sufficiently.

Next, the second reflective interface 16 is formed between the organic layer 13 having a refractive index n ₀ = 1.75 and the transparent layer 14 having a refractive index different from that of the organic layer 13 (for example, a refractive index of 2.0). The third reflective interface 16 is formed between the transparent layer 14 and the second electrode 12 having a different refractive index (for example, refractive index 1.8) from the transparent layer 14. Indium tin oxide (ITO) can be used as the material of the transparent layer 14 having a refractive index of 2.0, and the material of the second electrode 12 having a refractive index of 1.8 is changed, for example, by changing the composition of oxygen. ITO or the like can be used. In this case, at least one of the light reflection by the second reflection interface 16 and the light reflection by the third reflection interface 17 shifts the interference wavelength with respect to the center wavelengths λ1 and λ2 (λ12 ≠ λ13 or λ22 ≠ λ23), conditions for strengthening and weakening, and conditions for broadening the interference wavelength 2L12 / λ12 + φ2 / 2π = 1 + 1/2 (5) ′
2L22 / λ22 + φ2 / 2π = 1 (6) ′
2L13 / λ13 + φ3 / 2π = 3 (5) ′
2L23 / λ23 + φ3 / 2π = 2 + 1/2 (6) ′
λ22 = 380 nm <λ2-15 = 445 nm (7) ′
(The unit of λ12, λ22, λ13, and λ23 is nm)
Meet. φ2 and φ3 can be calculated in the same manner as described above.
As described above, all the conditions of the expressions (1) to (7) are satisfied.

  FIG. 3 shows a spectral transmittance curve of the interference filter by the first reflective interface 15 and the second reflective interface 16. In this case, since the wavelength conditions of the first reflective interface 15 and the second reflective interface 16 are different from each other by 15 nm or more, the transmittance is reduced in the vicinity of the wavelength of 550 nm. Can't get white light. Further, since a flat portion is not obtained in the spectral transmittance curve, the viewing angle characteristics show significant changes in both luminance and hue.

  FIG. 4 shows a spectral transmittance curve of the interference filter in which the effect of the third reflection interface 17 is added to the first reflection interface 15 and the second reflection interface 16. As can be seen from FIG. 4, interference filters that are substantially flat are formed in both the blue region and the green-red region of the spectral transmittance curve. The viewing angle characteristics of luminance and chromaticity in this state are shown in FIGS. As apparent from FIGS. 5 and 6, 85% or more of the luminance at the viewing angle of 0 degree is maintained at the viewing angle of 45 degrees, and the chromaticity deviation is also realized as Δuv ≦ 0.015.

  As described above, according to the first embodiment, in the organic EL element, the organic layer 13 sandwiched between the first electrode 11 and the second electrode 12 is monochromatic or visible light region 2. It has the 1st light emitting layer 13a and the 2nd light emitting layer 13b which light-emit the light of a mutually different color more than a color. A first reflective interface 15 is formed on the first electrode 11 side, and a second reflective interface 16 and a third reflective interface 17 are formed on the second electrode 12 side from which light is emitted. The distances L11, L21, L12, L22, L13, and L23 shown in FIG. 1 satisfy all of the expressions (1) to (6), and at least one of the expressions (7) and (8) is satisfied. It is set to be satisfied. As a result, this organic EL element has a high transmittance of the interference filter in a wide wavelength band, and can extract light well in a wide wavelength band. For this reason, according to this organic EL element, a white light-emitting element having a good hue can be realized. In addition, this organic EL element can greatly reduce the viewing angle dependence of luminance and hue for a single color or a composite color of two or more different colors. Moreover, this organic EL element can select a luminescent color with the design of the 1st light emitting layer 13a and the 2nd light emitting layer 13b. In addition, this organic EL element has low power consumption since the transmittance of the interference filter is high.

<2. Second Embodiment>
[Organic EL device]
In the organic EL device according to the second embodiment, the second reflective interface 16 and the third reflective interface 17 in the organic EL device according to the first embodiment are each divided into two front and rear reflective interfaces. (5) Expand the wavelength band of the antiphase interference condition shown in (6). That is, for example, with respect to the equation (5), when the second reflection interface 16 is divided into two reflection interfaces separated by Δ respectively in the front and rear, L12 becomes L12 + Δ and L12−Δ, and therefore the equation (5) is established. The band of λ12 is widened. The same applies to equation (6).

  According to the second embodiment, in addition to the same advantages as those of the first embodiment, the wavelength band of the antiphase interference condition expressed by the equations (5) and (6) can be expanded. The advantage that the viewing angle characteristics of the organic EL element can be further improved can be obtained.

<3. Third Embodiment>
[Organic EL device]
The portions of the light emitting layers a1 and a2 of the first light emitting layer 13a in the organic EL device according to the first embodiment have a laminated structure of a plurality of layers depending on the manufacturing method and required characteristics of the organic EL device. In some cases, the thickness may increase. The order of stacking the green light-emitting layer a1 and the red light-emitting layer a2 is the first from the first electrode 11 side in the shortest emission wavelength, that is, as in the first embodiment. Although it is desirable to stack the green light emitting layer a1 and the red light emitting layer a2 in this order from the electrode 11 side, the order of stacking the green light emitting layer a1 and the red light emitting layer a2 is reversed. It is possible that In such a case, since it is difficult to make the light emission center of the light emitting layer a1 and the light emission center of the light emitting layer a2 the same, it is difficult to maintain the viewing angle characteristics at a wide angle. As a countermeasure, by providing a new fourth reflective interface in addition to the first reflective interface 15, the second reflective interface 16, and the third reflective interface 17 in the organic EL element according to the first embodiment, The viewing angle characteristics can be improved.

  With respect to the fourth reflective interface, depending on the stacking order of the light emitting layer a1 and the light emitting layer a2, the conditions of both strengthening and weakening are within the range of the center wavelength ± 15 nm of the light emitting layer a1 and the light emitting layer a2. Exists. FIG. 7A shows the organic EL device according to the first embodiment. In this case, both the green light emitting layer a1 and the red light emitting layer a2 are sufficiently small in thickness, and the light emission center of the light emitting layer a1 is The light emission center of the light emitting layer a2 can be regarded as the same. On the other hand, as shown in FIG. 7B, when the thickness of the light emitting layer a1 for green light emission and the light emitting layer a2 for red light emission are relatively large, each 20 nm, the emission centers of these light emitting layers a1 and a2 Are considered offset from each other. As a result, as shown in FIG. 8, the spectral transmittance curves of the interference filters corresponding to the green light emitting layer a1 and the red light emitting layer a2 are inclined in opposite directions. For this reason, when the viewing angle increases, the transmittance of green light decreases, and conversely, the transmittance of red light increases and color shift occurs.

  Therefore, in the organic EL device according to the third embodiment, as shown in FIG. 9, another transparent transparent layer 18 having a refractive index different from that of the transparent layer 14 is provided on the transparent layer 14, and this transparent A second electrode 12 is provided on the layer 18. A fourth reflective interface 19 is formed between the transparent layer 18 and the second electrode 12. In this case, the third reflective interface 17 is formed between the transparent layer 14 and the transparent layer 18. The fourth reflective interface 19 is set at a position that satisfies the conditions for strengthening the light having the center wavelength 12 of the emission spectrum of the first light emitting layer 13a. Thus, the spectral transmittance curves of the interference filters corresponding to the green light emitting layer a1 and the red light emitting layer a2 are as shown in FIG. Thus, it can be seen that an interference filter having a flat peak portion can be formed.

  When the stacking order of the light emitting layer a1 for green light emission and the light emitting layer a2 for red light emission is reversed, the fourth reflective interface 19 is set to the center wavelength λ1 of the emission spectrum of the first light emitting layer 13a. The effect similar to the above can be obtained by forming at a position that is a condition of weakening.

  FIG. 11 and FIG. 12 show the viewing angle characteristics of the luminance and chromaticity of the organic EL device according to the third embodiment in which the fourth reflective layer 19 is formed. 11 and 12, it can be seen that according to this organic EL element, the viewing angle characteristics of luminance and chromaticity are further improved as compared with the organic EL element according to the first embodiment.

<Example 1>
Example 1 is an example corresponding to the first embodiment.
FIG. 13 shows an organic EL device according to Example 1. This organic EL element is a top emission type organic EL element. As shown in FIG. 13, in this organic EL element, a first electrode 11, an organic layer 13, a transparent layer 14, and a second electrode 15 are sequentially laminated on a substrate 20 in order from the lower layer. A passivation film 21 is provided thereon.

  The substrate 20 is made of, for example, a transparent glass substrate or a semiconductor substrate (for example, a silicon substrate), and may be flexible. The first electrode 11 is used as an anode electrode also serving as a reflective layer. For example, aluminum (Al), aluminum alloy, platinum (Pt), gold (Au), chromium (Cr), tungsten (W), etc. It is made of a light reflecting material. The first electrode 11 is preferably set to a thickness in the range of 100 to 300 nm. The first electrode 12 may be a transparent electrode. In this case, for the purpose of forming the first reflective interface 15 between the first electrode 12 and the substrate 20, a reflection made of a light reflecting material such as Pt, Au, Cr, W or the like is used. It is preferred to provide a layer.

  The organic layer 13 includes a hole injection layer 13c, a hole transport layer 13d, a first light-emitting layer 13a, an electron transport layer 13e, an electron injection layer 13f, a connection layer 13g, a hole transport layer 13h, and a second light-emitting layer 13b. The electron transport layer 13i and the electron injection layer 13j are sequentially stacked from the lower layer. The hole injection layer 13c is made of, for example, hexaazatriphenylene (HAT). The hole transport layer 13d is composed of, for example, α-NPD [N, N′-di (1-naphthyl) -N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine]. The The light emitting layer a1 for green light emission of the first light emitting layer 13a is made of, for example, Alq3 (triskinolinol aluminum complex), and the light emitting layer a2 for red light emission is made of, for example, rubrene as a host material doped with a pyromethene boron complex. Composed. The electron transport layer 13e is made of, for example, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline). The electron injection layer 13f is made of, for example, lithium fluoride (LiF). The connection layer 13g is made of, for example, Alq3 (8-hydroxyquinoline aluminum) doped with 5% of Mg, hexaazatriphenylene (HAT), or the like. The hole transport layer 13h that also serves as the hole injection layer is made of, for example, α-NPD. The second light emitting layer 13b is made of a light emitting material having a blue (B) emission color. Specifically, ADN (9,10-di (2-naphthyl) anthracene) is deposited as a host material to form a 20 nm-thick film. At this time, the film can be used as a blue light emitting layer by doping ADN with a diaminochrysene derivative as a dopant material in a relative film thickness ratio of 5%. The electron transport layer 13i is made of BCP, for example. The electron injection layer 13j is made of, for example, LiF.

  The thickness of each layer constituting the organic layer 13 is 1 to 20 nm for the hole injection layer 13c, 15 to 100 nm for the hole transport layer 13d, and 5 to 50 nm for the first light emitting layer 13a and the second light emitting layer 13b, respectively. The electron injection layers 13f and 13j and the electron transport layers 13e and 13i are preferably set in the range of 15 to 200 nm. The thickness of the organic layer 13 and each layer constituting the organic layer 13 is set to such a value that the optical film thickness enables the above-described operation.

  The second reflective interface 16 is formed by forming a conductive transparent layer 14 on the organic layer 13 and utilizing the refractive index difference between the organic layer 13 and the transparent layer 14. Further, the third reflective interface 17 is formed by utilizing the refractive index difference between the transparent layer 14 and the second electrode 12. The transparent layer 14 does not have to be a single layer, and may have a laminated structure of two or more transparent layers having different refractive indexes according to the required flat wavelength band and viewing angle characteristics.

The second electrode 12 from which light is extracted is made of ITO or an oxide of indium and zinc, which is generally used as a transparent electrode material, and is used as a cathode electrode. The thickness of the second electrode 12 is, for example, in the range of 30 to 3000 nm.
Note that the second electrode 12 can also serve as the transparent layer 14, and in this case, a second reflective interface 16 is formed between the organic layer 13 and the second electrode 12.

The passivation film 21 is made of a transparent dielectric. This transparent dielectric does not necessarily have a refractive index comparable to that of the material constituting the second electrode 12, and when the transparent layer 14 is also used by the second electrode 12 as described above, It is also possible to cause the interface between the second electrode 12 and the passivation film 21 to function as the second reflective interface 16 or the third reflective interface 17 using the difference in refractive index between them. As such a transparent dielectric, for example, silicon dioxide (SiO ₂ ), silicon nitride (SiN), or the like can be used. The thickness of the passivation film 21 is, for example, 500 to 10,000 nm.

  If necessary, a translucent reflective layer may be provided between the organic layer 13 and the transparent layer 14. This translucent reflective layer is composed of, for example, a metal layer such as magnesium (Mg), silver (Ag), or an alloy thereof, and the thickness is preferably set to 5 nm or less, preferably 3 to 4 nm or less. .

<Example 2>
Example 2 is an example corresponding to the first embodiment.
FIG. 14 shows an organic EL device according to Example 2. This organic EL element is a bottom emission type organic EL element. As shown in FIG. 14, in this organic EL element, a passivation film 21, a second electrode 12, an organic layer 13, and a first electrode 11 are sequentially laminated on a transparent substrate 20 in order from the lower layer. In this case, light emitted from the second electrode 12 side passes through the substrate 20 and is extracted outside. The transparent layer 14 of Example 1 is also used as the second electrode 12. A second reflective interface 16 is formed between the organic layer 13 and the second electrode 12, and a third reflective interface 17 is formed between the second electrode 12 and the passivation film 21. Others are the same as in the first embodiment.

<4. Fourth Embodiment>
[Organic EL lighting device]
FIG. 15 shows an organic EL lighting device according to the fourth embodiment.
As shown in FIG. 15, in this organic EL lighting device, an organic EL element 31 according to any one of the first to third embodiments is mounted on a transparent substrate 30. In this case, the organic EL element 31 is mounted on the substrate 30 with the second electrode 12 side down. For this reason, the light emitted from the second electrode 12 side passes through the substrate 30 and is extracted outside. A sealing substrate 32 is provided so as to face the substrate 30 with the organic EL element 31 interposed therebetween, and the sealing substrate 32 and the outer peripheral portion of the substrate 30 are sealed with a sealing material 33. The planar shape of the organic EL lighting device is selected as necessary, and is, for example, a square or a rectangle. Although only one organic EL element 31 is shown in FIG. 15, a plurality of organic EL elements 31 may be mounted on the substrate 30 in a desired arrangement as necessary. The details of the configuration of the organic EL lighting device other than the organic EL element 31 and the configuration other than the above are the same as those of a conventionally known organic EL lighting device.

  According to the fourth embodiment, since the organic EL element 31 according to any one of the first to third embodiments is used, the angle dependency is small, in other words, the intensity and color depending on the illumination direction. It is possible to realize an organic EL lighting device that is a surface light source that has very little change and has good light distribution characteristics. In addition to white light emission, various light emission colors can be obtained by selecting the light emission color of the organic EL element 31 according to the design of the first light emission layer 13a and the second light emission layer 13b. An organic EL lighting device can be realized.

<5. Fifth Embodiment>
[Organic EL display device]
FIG. 16 shows an organic EL display device according to the fifth embodiment. This organic EL display device is an active matrix type.
As shown in FIG. 16, in this organic EL display device, a drive substrate 40 and a sealing substrate 41 are provided so as to face each other, and an outer peripheral portion of these drive substrate 40 and sealing substrate 41 is a sealing material 42. It is sealed by. In the drive substrate 40, for example, pixels made of the organic EL elements 43 according to any one of the first to third embodiments are formed in a two-dimensional array on a transparent glass substrate. On the drive substrate 40, a thin film transistor is formed as an active element for pixel drive for each pixel. On the driving substrate 40, scanning lines, current supply lines, and data lines for driving the thin film transistors of the respective pixels are further formed vertically and horizontally. A display signal corresponding to each display pixel is supplied to the thin film transistor of each pixel, and the pixel is driven according to the display signal to display an image. Details of the configuration of the organic EL display device other than the organic EL element 43 and configurations other than those described above are the same as those of a conventionally known organic EL display device.

  This organic EL display device can be used not only as a monochrome display device but also as a color display device. When this organic EL display device is used as a color display device, an RGB color filter is provided on the drive substrate 40 side, specifically between the second electrode 12 of the organic EL element 43 and the drive substrate 40, for example. .

  According to the fifth embodiment, by using the organic EL element 31 according to any one of the first to third embodiments, a high-quality organic image with extremely little variation due to the viewing angle of luminance and hue. An EL display device can be realized.

Although the embodiments and examples of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments and examples, and various modifications based on the technical idea of the present invention. Is possible.
For example, the numerical values, structures, configurations, shapes, materials, and the like given in the above-described embodiments and examples are merely examples, and different numerical values, structures, configurations, shapes, materials, etc. are used as necessary. Also good.

  DESCRIPTION OF SYMBOLS 11 ... 1st electrode, 12 ... 2nd electrode, 13 ... Organic layer, 13a ... 1st light emitting layer, 13b ... 2nd light emitting layer, 14 ... Transparent layer, 15 ... 1st reflective interface, 16 ... Second reflective interface, 17 ... third reflective interface, 18 ... transparent layer, 19 ... fourth reflective interface, 20 ... substrate, 21 ... passivation film, 30 ... substrate, 31 ... organic EL element, 32 ... sealing Substrate 33 ... Sealing material 40 ... Driving substrate 41 ... Sealing substrate 42 ... Sealing material 43 ... Organic EL element

Claims (15)

A first light emitting layer and a second light emitting layer, which are sandwiched between a first electrode and a second electrode and emit light of a single color in a visible light region or different colors of two or more colors, are provided in the first light emitting layer. An organic layer sequentially including at positions separated from each other in a direction from the electrode toward the second electrode;
A first reflective interface provided on the first electrode side for reflecting light emitted from the first light-emitting layer and the second light-emitting layer and emitting the light from the second electrode side; ,
A second reflective interface and a third reflective interface sequentially provided at positions separated from each other in a direction from the first electrode toward the second electrode on the second electrode side;
The optical distance between the first reflective interface and the light emission center of the first light emitting layer is L11, and the optical distance between the first reflective interface and the light emission center of the second light emitting layer is L21, L12 represents the optical distance between the light emitting center of the first light emitting layer and the second reflective interface, and L22 represents the optical distance between the light emitting center of the second light emitting layer and the second reflective interface. L13 represents an optical distance between the light emitting center of the first light emitting layer and the third reflective interface, and L23 represents an optical distance between the light emitting center of the second light emitting layer and the third reflective interface. When the central wavelength of the emission spectrum of the first light emitting layer is λ1 and the central wavelength of the emission spectrum of the second light emitting layer is λ2, L11, L21, L12, L22, L13 and L23 are expressed by the following formula (1 ) To (6) are satisfied, and a smaller number of the formulas (7) and (8) A light-emitting element that satisfies at least one of the requirements.
2L11 / λ11 + φ1 / 2π = 0 (1)
2L21 / λ21 + φ1 / 2π = n (where n ≧ 1) (2)
λ1-150 <λ11 <λ1 + 80 (3)
λ2-30 <λ21 <λ2 + 80 (4)
2L12 / λ12 + φ2 / 2π = m ′ + 1/2 and 2L13 / λ13 + φ3 / 2π = m ″ or 2L12 / λ12 + φ2 / 2π = m ′ and 2L13 / λ13 + φ3 / 2π = m ″ +1/2 (5)
2L22 / λ22 + φ2 / 2π = n ′ + 1/2 and 2L23 / λ23 + φ3 / 2π = n ″ or 2L22 / λ22 + φ2 / 2π = n ′ and 2L23 / λ23 + φ3 / 2π = n ″ +1/2 or 2L22 / λ22 + φ2 / 2π = n ′ + 1/2 and 2L23 / λ23 + φ3 / 2π = n ″ +1/2 (6)
λ22 <λ2-15 or λ23> λ2 + 15 (7)
λ23 <λ2-15 or λ22> λ2 + 15 (8)
However, m ′, m ″, n, n ′, n ″: integers λ1, λ2, λ11, λ21, λ12, λ22, λ13, λ23 are in units of nm.
φ1: Phase change when light of each wavelength is reflected by the first reflection interface φ2: Phase change when light of each wavelength is reflected by the second reflection interface φ3: Light of each wavelength is the third Phase change when reflected at the reflective interface   The light-emitting element according to claim 1, wherein the peak of the spectral transmittance curve of the interference filter of the light-emitting element is substantially flat or the slopes of all emission color bands are substantially equal to each other.   The light emitting device according to claim 2, wherein a decrease in luminance when the viewing angle is 45 degrees is 30% or less with respect to the luminance when the viewing angle is 0 degrees, and chromaticity deviation Δuv ≦ 0.015.   The light emitting device according to claim 3, wherein n = 1.   The light-emitting element according to claim 1, wherein the first electrode, the organic layer, and the second electrode are sequentially stacked on a substrate.   The light emitting device according to claim 5, wherein an outer side of the third reflective interface is formed by a transparent electrode layer, a transparent insulating layer, a resin layer, a glass layer, or an air layer having a thickness of 1 μm or more.   The light-emitting element according to claim 1, wherein the second electrode, the organic layer, and the first electrode are sequentially stacked on a substrate.   The light emitting device according to claim 7, wherein the outside of the third reflective interface is formed of a transparent electrode layer, a transparent insulating layer, a resin layer, a glass layer, or an air layer having a thickness of 1 µm or more.   The light-emitting element according to claim 1, wherein a metal layer having a thickness of 5 nm or less is provided between the second light-emitting layer and the second electrode.   The light emitting device according to claim 1, wherein at least one of the first reflective interface, the second reflective interface, and the third reflective interface is divided into a plurality of reflective interfaces.   When the light emission center of the light emitting layer that emits light of two or more different colors among the first light emitting layer and the second light emitting layer cannot be regarded as the same, the spectrum of the interference filter of the light emitting element The light emitting device according to claim 1, further comprising a reflective layer for maintaining the flatness of the peak of the transmittance curve. Having at least one light emitting element,
The light emitting element is
A first light emitting layer and a second light emitting layer, which are sandwiched between a first electrode and a second electrode and emit light of a single color in a visible light region or different colors of two or more colors, are provided in the first light emitting layer. An organic layer sequentially including at positions separated from each other in a direction from the electrode toward the second electrode;
A first reflective interface provided on the first electrode side for reflecting light emitted from the first light-emitting layer and the second light-emitting layer and emitting the light from the second electrode side; ,
A second reflective interface and a third reflective interface sequentially provided at positions separated from each other in a direction from the first electrode toward the second electrode on the second electrode side;
The optical distance between the first reflective interface and the light emission center of the first light emitting layer is L11, and the optical distance between the first reflective interface and the light emission center of the second light emitting layer is L21, L12 represents the optical distance between the light emitting center of the first light emitting layer and the second reflective interface, and L22 represents the optical distance between the light emitting center of the second light emitting layer and the second reflective interface. L13 represents an optical distance between the light emitting center of the first light emitting layer and the third reflective interface, and L23 represents an optical distance between the light emitting center of the second light emitting layer and the third reflective interface. When the central wavelength of the emission spectrum of the first light emitting layer is λ1 and the central wavelength of the emission spectrum of the second light emitting layer is λ2, L11, L21, L12, L22, L13 and L23 are expressed by the following formula (1 ) To (6) are satisfied, and a smaller number of the formulas (7) and (8) A lighting device that satisfies at least one of these requirements.
2L11 / λ11 + φ1 / 2π = 0 (1)
2L21 / λ21 + φ1 / 2π = n (where n ≧ 1) (2)
λ1-150 <λ11 <λ1 + 80 (3)
λ2-30 <λ21 <λ2 + 80 (4)
2L12 / λ12 + φ2 / 2π = m ′ + 1/2 and 2L13 / λ13 + φ3 / 2π = m ″ or 2L12 / λ12 + φ2 / 2π = m ′ and 2L13 / λ13 + φ3 / 2π = m ″ +1/2 (5)
2L22 / λ22 + φ2 / 2π = n ′ + 1/2 and 2L23 / λ23 + φ3 / 2π = n ″ or 2L22 / λ22 + φ2 / 2π = n ′ and 2L23 / λ23 + φ3 / 2π = n ″ +1/2 or 2L22 / λ22 + φ2 / 2π = n ′ + 1/2 and 2L23 / λ23 + φ3 / 2π = n ″ +1/2 (6)
λ22 <λ2-15 or λ23> λ2 + 15 (7)
λ23 <λ2-15 or λ22> λ2 + 15 (8)
However, m ′, m ″, n, n ′, n ″: integers λ1, λ2, λ11, λ21, λ12, λ22, λ13, λ23 are in units of nm.
φ1: Phase change when light of each wavelength is reflected by the first reflection interface φ2: Phase change when light of each wavelength is reflected by the second reflection interface φ3: Light of each wavelength is the third Phase change when reflected at the reflective interface Having at least one light emitting element,
The light emitting element is
A first light emitting layer and a second light emitting layer, which are sandwiched between a first electrode and a second electrode and emit light of a single color in a visible light region or different colors of two or more colors, are provided in the first light emitting layer. An organic layer sequentially including at positions separated from each other in a direction from the electrode toward the second electrode;
A first reflective interface provided on the first electrode side for reflecting light emitted from the first light-emitting layer and the second light-emitting layer and emitting the light from the second electrode side; ,
A second reflective interface and a third reflective interface sequentially provided at positions separated from each other in a direction from the first electrode toward the second electrode on the second electrode side;
The optical distance between the first reflective interface and the light emission center of the first light emitting layer is L11, and the optical distance between the first reflective interface and the light emission center of the second light emitting layer is L21, L12 represents the optical distance between the light emitting center of the first light emitting layer and the second reflective interface, and L22 represents the optical distance between the light emitting center of the second light emitting layer and the second reflective interface. L13 represents an optical distance between the light emitting center of the first light emitting layer and the third reflective interface, and L23 represents an optical distance between the light emitting center of the second light emitting layer and the third reflective interface. When the central wavelength of the emission spectrum of the first light emitting layer is λ1 and the central wavelength of the emission spectrum of the second light emitting layer is λ2, L11, L21, L12, L22, L13 and L23 are expressed by the following formula (1 ) To (6) are satisfied, and a smaller number of the formulas (7) and (8) A display device that satisfies at least one of the requirements.
2L11 / λ11 + φ1 / 2π = 0 (1)
2L21 / λ21 + φ1 / 2π = n (where n ≧ 1) (2)
λ1-150 <λ11 <λ1 + 80 (3)
λ2-30 <λ21 <λ2 + 80 (4)
2L12 / λ12 + φ2 / 2π = m ′ + 1/2 and 2L13 / λ13 + φ3 / 2π = m ″ or 2L12 / λ12 + φ2 / 2π = m ′ and 2L13 / λ13 + φ3 / 2π = m ″ +1/2 (5)
2L22 / λ22 + φ2 / 2π = n ′ + 1/2 and 2L23 / λ23 + φ3 / 2π = n ″ or 2L22 / λ22 + φ2 / 2π = n ′ and 2L23 / λ23 + φ3 / 2π = n ″ +1/2 or 2L22 / λ22 + φ2 / 2π = n ′ + 1/2 and 2L23 / λ23 + φ3 / 2π = n ″ +1/2 (6)
λ22 <λ2-15 or λ23> λ2 + 15 (7)
λ23 <λ2-15 or λ22> λ2 + 15 (8)
However, m ′, m ″, n, n ′, n ″: integers λ1, λ2, λ11, λ21, λ12, λ22, λ13, λ23 are in units of nm.
φ1: Phase change when light of each wavelength is reflected by the first reflection interface φ2: Phase change when light of each wavelength is reflected by the second reflection interface φ3: Light of each wavelength is the third Phase change when reflected at the reflective interface   A driving substrate provided with an active element for supplying a display signal corresponding to each display pixel to the light emitting element; and a sealing substrate provided opposite to the driving substrate, wherein the light emitting element The display device according to claim 13, wherein the display device is disposed between a driving substrate and the sealing substrate.   The color filter which permeate | transmits the light inject | emitted from the said 2nd electrode side is provided in the board | substrate by the side of the said 2nd electrode of the said light emitting element of the said drive substrate and the said sealing substrate. Display device.

Images